use same type to ease bean replication

git-svn-id: https://svn.apache.org/repos/asf/archiva/sandbox/trunk@1486321 13f79535-47bb-0310-9956-ffa450edef68
use long rather than Date for cassandra storage

git-svn-id: https://svn.apache.org/repos/asf/archiva/sandbox/trunk@1486322 13f79535-47bb-0310-9956-ffa450edef68